Add siraben to contributors

Author: siraben

src/contributors.rst

@@ -19,3 +19,4 @@ Reviewers:
 - Sylvain Henry `@hsyl20 <https://hsyl20.fr/home/>`_
 - Frank Staals  `@noinia <https://fstaals.net/>`_
 - Andrew Lelechenko `@bodigrim <https://github.com/Bodigrim>`_
+- Ben Siraphob `@siraben <https://siraben.dev>`_